Machine and humidity responsive control therefor



Feb. 26, 1946. J. c. LEDBETTER ET AL 2,395,737

MACHINE AND HUMIDITY RESPONSIVE CONTROL THEREFOR Filed Se pt 28, 1939 3 Sheets-Sheet l INVENTORS JAMES CTLE'DBETTfI? 450M449!) h. Pfi/TCHA/PD ELSE/7T n. SHERMAN 5y i ATTORNEYS Feb. 26, 1946: J. c. LEDBETTER ET AL v12,395,737

MACHINE AND HUMIDITY RESPONSIVE CONTROL THEREFOR Filed Sept. 28, 1939 3 Sheets-Sheet 2 91 7 9 :IZ 'I:I 1\ 80 O I V I V w g 16 -I 90 25 I I i v -67 89 W I Q 23 03 87 21 85 24 86 C a 6 v a ou or;

33* I as CLOTH 8| GLA new/mos 78 coTm/v 01.0717 32. FELT 78 INVENTORS JAMES C. LEDBETTEI? [OW/1RD M PR/TCHA/FO ELBEAT W SHERMAN 1 BY MM Jam A'TTORNEYS Feb. 2 1946 J. c. LEDBETTER ET AL 2,395,787

MACHINE AND HUMIDITY RESPONSIVE CONTROL THEREFOR Filed Sept. 28, 1939 3 Sheets-sheaf 3 INVENTORS JAMES GLEOBETTER EDWARD M PRITCHARD [LEE/FT MSHEFMAN BY ATTORNEYS Patented Feb. 26, 1946 MACHINE AND HUMIDITY RESPONSIVE CONTROL THEREFOR James C. Ledbetter, Edward M. Pritchard, and Elbert W. Sherman, New York, N. Y., assignors to The Prosperity Company, Inc., Syracuse, N. Y., a corporation of New York Application September 28, 1939, Serial No. 296,927

4 Claims.

This invention relates to machines for performing operations on articles or work pieces in course of production, and to control apparatus responsive to variations of the moisture content or humidity of the articles being operated upon. A machine convenient for illustrating the invention is a textile press, say a laundry-ironing press, used in the textile ironing or smoothing art; and

the invention more particularly relates to a ma-- chine and humidity responsive control therefor, and which we sometimes refer to as a humidity press timer.

Conventional laundry-ironing presses used in commercial laundries and the like, also other types of textile presses of a variety of uses, are'ordinarily of the jaw-motion type having coacting pressing members or pressing jaws usually called the head and buck, which open and close on the work. 'These presses are power driven, that is, they are usually closed and held closed by motor means which subjects the work to a high degree of sustained ironing or finishing pressure under heat.

One or both pressing jaws (head and buck) of present-daypresses are heated, usually by steam,

tons which are spaced suificiently far apart to require actuation (usually depressed) by the both hands 01' an operator for the purpose of energizing the motor means and closing the press.

According to present practice, either an electrically-operated or a fluid-pressure operated motor means is employed to drive or close laun y and other textile presses. The fluid-pressure or pneumatic type of moto means is now largely in use as the most convenient form of motive force to not only close a press but in particular to maintain it closed under said motive force during the period of time required to iron the damp work.

This type of driving force, maintained or applied to the closed pressing jaws, follows up any de pression of the padding on the buck so as to keep the work under uniformly sustained pressure during the ironing period and thus produces a, uniform quality of work.

for pressure-ironing and finishing the damp laundered work in a dry condition. and for imparting thereto a desirable firm smooth finish, which fin-- ish in some cases may be said to have a luste or sheen. Such finish on laundry work can only be obtained by pressure-ironing with power ironing machine methods now sought after in the commercial laundry trade as the most effective and economical production of laundry work. The better grade of firm smooth finish on washed goods cannot be obtained by the hand-ironing method which is laborious, expensive, and lacks in satisfactory production and results.

The upper pressing head of a conventional laundry-ironing press has a metallic plated or polished surface to produce the requisite finish. while the lower buck has a padded surface acting as a yielding bed on which to effectively iron the laundered work which is damp when spread upon the padded buck. The ironing pad permits the buttons, seams, and other irregularities to be depressed into the yielding bed in order to equalize the pressure 01' the head around these parts of the work, as the head seal down and is maintained by the motor means under final heavy-ironing pressure until the work is ironed dry and finished.

At the present stage oi the art, the operation of the motor means of laundry and other textile presses is usually governed by a two-hand control means comprising two safety manuals or but- One of the more generally used laundry presses is sometime referred to as the full automatic" press by reason of its movable pressing Jaw or jaws being fully powered to close the press all the way from wide-open to fully-closed position by motor means. Thus a full-automatic laundry press having an air-pressure motor means is chosen for illustrating this invention, but it is pointed out that the invention may be used in connection with a manually-operated press, say a foot-operated press.

- In operating a laundry ironing press, the damp laundered work is laid and smoothed on the buck, and then the ironing head is closed down upon the work and maintained closed under resilient pressure. An ironing temperature of about 350 is maintained in one or both pressing jaws, and when the head touches the damp work the heat changes the moisture in the work to stem, which, in expanding, passes out of the work into the padded buck and is absorbed therein or dissipates into the atmosphere. The heat and jaw compression drives the moisture from the work and dries it with the firm smooth finish heretofore explained.

In considering one .of the more important problems of commercial-laundry ironing, it is next explained that it is highly desirable that an ironing press open instantly the work is pressure-ironed. If the press-opens too. soon the work isinsufllciently ironed and does not have a firm-smooth finish, and it closed too long the work is excessively ironed and its finish may be impaired or the work may scorch not to mention the loss of time in the ironing operation. Thus,

the invention seeks to avoid the under-ironing or over-ironing of laundered work.

Almost every damp article or work piece will have a different drying time, depending on its size and thickness as well as its moisture content. An article having several thicknesses of cloth or made of heavy yarn or thread takes longer to iron dry and attain the desirable laundry finish, than one having only one thickness or loosely woven out of light weight threads. Hence, it will be necessary to maintain the press closed much longer for certain classes of work than for others.

Heretofore, the time required for producing the desired ironing finish on the laundered work has been judged and timed by the operator, and more recently in the art by an automatic timer adapted to laundry presses. The operator or the timer, as the case may be, releases and opens the press when the ironing is supposedly complete. However, the most expert operator cannot make uniformly correct guesses of the pressing or ironing time necessary for a large number and variety of articles, either to manually open the press, or to pre-set the automatic press timer. The result is that under present-day practice the work produced may vary considerably in the quality of the finish.

The more modern type of conventional laundr press with a timer does not solve the problem because the timer is itself dependent upon the operator for predetermining the ironing time and pro-setting the timer for controlling the opening of the press. Conventional laundry press timers, once set or adjusted, have a fixed ironing period and make no provision for variation of the head and buck ironing temperature, or the moisture content in the work, or the difference in character of various laundered pieces coming to the press.

In carrying our invention into practice, we have provided, among other things, an electric circuit with moisture-responsive electrode terminals forming a new combination in a textile press which automatically opens the press at the exact moment the damp work is dried and ironed; and in addition thereto, we have combined therewith several examples of control means by which the closing of the press is rendered safe to the operator in a new way. Incidentally, we employ an electronic circuit in disclosing the principles of this invention.

It is, therefore, one of the objects of the invention to provide a control instrumentality for a machine,.such as a laundry press, by means of which it automatically opens when the humidity or moisture content of the article being operated upon has reached a predetermined amount, so that the operator of the laundry press need not guess at the time required to pressure-iron the work, whereb the press turns out a uniform quality or finished work on a production basis.

Also, an import it object of this invention is o produce an automatic press timer for opening press, whether power operated or manually op rated, after the damp war; is completely presure=ironed, so avoid under-ironing or overrcning or" the work, wherein the operation of press a .ion of the dissipation u'midity or moisture the work piece, a function or" the time gauged by an partially or preliminarily closed, to take the control away from the operator and automatically continue the closing of the press, and then deliver said auxiliary control to a humidity responsive press timer which holds the press closed under motive force for the exact ironing time.

Another object is to provide a moisture responsive control instrumentality for a machine which performs an operation upon a dampened article, by means of which the value of an electric current is caused to vary in accordance with the varying resistance interposed by the changing or reduction 01 the moisture in the article or work, and the machine is controlled by such current variation.

Another object is to provide a laundry press with means in the buck which responds to the moisture driven out or the work being pressed, so as to automatically and instantly open the press at the exact moment when the work is pressure-ironed.

Still another object is to provide an electric control circuit means, responsive to the variation of humidity in the work, for controlling a load or power circuit.

The drawings Other objects and advantages of this invention will be apparent from the following description written in connection with the accompanying drawings showing several examples of the invention, wherein:

Figure 1 is a diagrammatic side view of a poweroperated laundry-ironing press in open position and having electric two-hand control means for closing it, in combination with our first form of moisture or humidity-responsive electrical circuit Ior opening the press at the exact moment the work is pressure-ironed.

Figure 2 is a similar view of the press, except that it is in preliminary closed position, that is, nearly closed; and the two-hand buttons have been released by the operator and returnedto normal position, the moisture or humidity-responsive device having taken the control away from the two hand control. The humidity responsive press-timer circuit is enclosed within a box, which, in actual practice, is attached to the press.

Figure 3 is a fragmentary cross-sectional view oi a buck, showing a new padding assembly therefor, the padding containing one form of the electrode means (our first form thereof) next shown in Figure 4.

Figure 4 is a plan view of said first form of press-timer moisture-responsive electrode means adapted for use within the padding of Figure 3. The padding is removed, but the electrode is shown superimposed on the buck. This is a single electrode which forms one terminal or side of the electronic circuit to be described.

Figure 5 is a plan view of a buck (without padding) showing a second form of the moistureresponsive electrode means. This is a double electrode forming both terminals of the control circuit.

Figure 6 is a sectional end view of an ironing head, showing a third iorm of electrode means which is carried in the ironing head; and this form renders it unnecessary to employ electrode means in the buck.

Description of conventional ironing press For the purpose of illustrating this invention, a simple or elementary form of power-operated laundry press is shown. Known types most generally employ a stationary lower buck and movable upper ironing head, although in som con. structions both the head and buck are movable. In other instances, the buck moves in and out of registration with the stationary head. However, all textile presses are of one form or another having jaw motion, in that the work is pressed between two or more pressing jaw members, one or the other or both of which are power operated.

The press illustrated herein has a frame I with a work table 2 under the pressing jaws, that is, under the coacting head and buck. An ironing buck or bed 3 is mounted stationary on the frame. and has the usual form of padding 4 on its ironing surface. A movable ironing head I is carried on the forward end of a head arm or lever i pivoted at I on the frame. The heads and bucks of pressing machines are manufactured in a variety of shapes and sizes best suited to particular apparel and textile materials to be'pressed.

The head 5 and buck 3 may be hollow, that is, each may have the usual steam chamber through which steam is circulated to provide an ironing temperature, and flexible steam connections 8 for the ironing head may be used in a way known to the art. Also, the buck 3 has the usual steam chamber it (Figure 3) and steam connections II seen in Figure 1. t

A head-operating lever B lifts the head [high above the buck 3 to fully expose the padded sursequently a wide opening is afforded for the 'convenience of the operator. This type of press, with its wide opening head. swingable up and down in relation to the buck around the rear horizontal axis I, is sometimes called the "scissors-action type of full-automatic press. It is one of the more convenient forms of machines by which to disclose this invention.

A conventional form of power-actuating means is shown for closing and opening the press. The motor means may perform both functions, that is the opening and closing cycle, but moregenerally the motor means is employed to close the press and simultaneously stretch or load a spring counterbalance, whereupon the latter performs the reverse function of opening the press and holding it open. As known in the art, an electric or other.

motor means may be employed, but the example shown comprises a pneumatic motor means it usually operated by air pressure.

The cylinder I8 is mounted to oscillate on a frame pivot is and its piston 20 with connecting rod 2! is pivotally connected at 22 to the head arm 8. Any suitable form of head counterbalancing means may be employed, and usually this takes the form of a long coil spring 23, having one end attached at 24 to the press frame and its other end operatively connected at 25 to the head arm. with the motor means I! idle or deenergized, the tensioned spring means 23 maintains the press in wide open position.

An air inlet and exhaust tube 26 communicates with the inner or closed end of the cylinder, and

- ate the press.

course be employed in place of the fluid-Dower valve means 21. The magnetically controlled or solenoid valve is shown diagrammatically. It has a stem '20 which carries a solenoid core or armature 28 adapted to be actuated (pulled down) by a magnet coil or solenoid winding 30. A spring II normally raises the valve stem when the solenoid is deenergized, and the energization .of the solenoid returns it against the tension of the spring to its lowermost position. The valve described is a poppet type valve and is found to be satisfactory for use in this new combination when a pneumatic motor means is used to oper- An air-pressure supply conduit 32 connects with the valve housing 21 to feed air under pressure to the flexible hose 26 from a compressor and tank which have not been shown. An inlet valve head is carried on the inner end of the valve stem 20 and is held open by the action of g the solenoid, that is, unseated from its inlet port against the yielding buck pad 4 and to compensate or take up for any give or compression in the pad. Thus, when thepress is closed, the

motor I! is stalled against further movement by the contact of the head with the buck, the pressure of air continuing to urge the two together under ironing compression.

An exhaust valve head It acts to close an ex! haust port 38' when the inlet valve 33 is open.

The inlet valve II and exhaust valve 35 are fixed on the valve stem 28 and work in unison. Thus.

this usually is an air hose which flexes with the up and down movement of the cylinder. A con-v when the inlet valve 33 is open. the exhaust valve '35 is closed and the press is closing or closed. And conversely, when the inlet valve 33 is seated on the inlet port 34, the exhaust valve 3! is open to exhaust the motor cylinder 18 through the exhaust port 36 to atmosphere. and the press is open or in the act of opening.

The foregoing features of construction are presented as an exemplary form of power-actuated textile press for laundry or other work, for the purpose of explaining the control "instrumentalities combined therewith and constituting this invention now explained by reference to several examples of construction which have given satisfactory results.

The two-hand electric control it closed under power during the period the work piece I6 is still damp, and to open the press when the work has become sumciently dry and is pressure-ironed.

In order to energize the relay 31, there is provided a gas-filled thermionic tube 38 which may be of the heater type. having a heating filament 39, a cathode 40, a control electrode or grid I and an anode 42. This tube may be filled with an ionizable gas, such as a mixture of argon and neon, 'at a reduced pressure. We prefer to operate tlie tube entirely on alternating current, and for this purpose a transformer 43 has a primary 44 which is connected between wires 65 and II leading to a switch 41 connected across the 60 cycle alternating current power supply mains 48. The transformer 43 may have a low voltage secondary 49 which may be connected directly to the filament 39 for energizing the filament.

The transformer 43 may also be provided with a higher voltage secondary winding 50 for providing suitable operating voltages for the other elements of the tube. The cathode is connected to a point 5! on this secondary winding 50, and the opposite ends of the windings may be connected to the control electrode 4| and anode 42 to thus give said control electrode a more negative potential than the cathode whenever the anode is given a positive potential. Thus, the end 52 of the secondary winding is connected by a wire 53 through resistances 54 and 55 and resistance 56 to the control grid 4|, these resistances being in series. The resistance 55 is preferably made variable and for convenience the two resistances 54 and 55 are used, although one might be used to take the place of these two if desired. A condenser 51 is used to bridge the resistance 56. The other end 58 of the secondary winding 50 may be connected through a resistance 59 and the coil 50 of the relay 31 to the anode 42 by means of a wire 6|. A condenser 62 is shunted across the relay coil 50 in order to store up and smooth out the half cycle pulses produced when the anode current is flowing. The tube 38, relay 31, transformer 43, associated resistances 54, 55 and 56 with other circuit parts, are carried in a housing 31' (Figure 2) and mounted on the press.

The relay 31 is provided with an armature 53 which has a contact 64 adapted to engage a stationary contact 65. The contact 54 is connected by a wire 66 to one end of the solenoid 30, while the other end of the solenoid is connected to the wire 46 forming one side of the alternating current power supply 48. The contact is connected to the wire 45 forming the other side of the power supply. When the relay 31 is energ zed, the armature 53 closes the contacts 64 and 65, thus causing current t flow from the wire 45 through contacts 55 and 64, wire 66, solenoid 30, and back to wire 46. Energizing the relay 31 therefore will energize the solenoid 30 and operate the pneumatic valve 21 to open its inlet valve 33 and close its exhaust valve 35.

Means may be provided to manually control the operation of the tube 38 to energize the re lay 31 so that the solenoid 30 may he energized to close the press. To this end, a pair of manually operated button switches 61 and 58 may be connected in series, the switch 68 being connected by a wire 58 to a point 10 on the control grid circuit between the resistances 55 and 55. The other switch 81 may be connected by a wire 1! to the cathode 4B of the tube 38.

When the two-hand switches 61 and 68 are depressed, so that the point 10 in the control grid circuit is connected to the cathode 40, the portion or" the transformer secondary coil 50 between the points 5! and 52 is connected across the resistances .35 and 55 and the control grid 41 is connected directly to the cathode 40 through the resistance This tends to change the potential of the control grid towards the cathode potential, with the result that the control grid becomes more positive and current flows in the anode circuit of the tube, thus energizing the relay 3?.

Therefore, to close the press, the operator has only to depress switch buttons 81 and 58 and the solenoid 30 will be energized and the ironing head 5 brought down upon the buck. The switches 51 and 68 are spaced far enough apart on the front edge or apron of the table 2, so that they will require both hands of the operator to depress them and thus provide a safety feature. Both the operator's hands must be away from the buck 3 when the head 5 is closed down upon it.

The moisture responsive control of Figure 1 and its operation When the heated head 5 strikes the damp article [6 laid on the buck, the moisture contained therein is forced out, partly by the pressure of the head against the buck which squeezes the article, but mostly because of the temperature of the head which is such that any water contained in the article is turned to steam. The moisture being thus driven out of the article is used to further control the operation of the press. For this purpose, the buck 3 is preferably constructed in a particular manner to provide an electrode 12 (Figure 4) which is sensitive to the presence of moisture.

The buck 3 may be built up with a series of padding layers of various materials to make it somewhat resilient, so that any unevenness in the article to be pressed, such as buttons, seams and the like, may be forced into the padding under pressure of the head. The lower hollow portion [4 of the buck may first be covered with an insulating layer 13 (such as varnish impregnated glass cloth) upon which may be placed a spring assembly comprising a metal sheet 14 carrying a plurality of springs 15, arranged close together and anchored to the sheet. Above the springs 15 we preferably provide a layer of felt 15, and on top of this a cottom cloth 11 which may be large enough to come down over the side edges of the buck to be laced securely in place or otherwise attached to the lower supporting section thereof.

Upon the top of the cotton cloth 11, we preferably place the electrode 12 which, in one form of the invention, may comprise a plurality of strips 18 (Figure 4), running lengthwise of the buck in spaced relation to each other, and a plurality of cross strips 19, arranged crosswise of the buck and making electrical contact with the strips 18. We have found it preferable to use aluminum for the electrode because it does not corrode or otherwise react with the water contained in the articles being pressed, which in some cases may be slightly acidified, and which therefore will not produce unseemly stains on the buck cover which might color the article being pressed. We have found it desirable to use extremely thin aluminum foil for this purpose, and for convenience the strips 18 and 19 may be cemented to the cotton cloth 11 to hold them in place when the press is in operation, although care'should be taken that good electrical contact is made where the strips cross each other. A wire may connect to any one of the strips for l raking electrical connection with the entire elect ode J2.

The insulatin material 13 below the spring assembly is preferably of such a character that it will not be affected by moisture or heat, and we have found that varnish-impregnated glass insu- Eating cloth is excellent for this purpose. When the moisture is driven out of the article it tends to penetrate the interior of the buck padding, and where the spring assembly rests directly on the acts as a second electrode.

s ears? metallic portion it of the buch 8, the moisture in the felt pad 16 and cotton cloth Ti may tend to short circuit the electrode it to the metal frame of the press. The glass-impregnated insulating cloth 1% tends to prevent this, as it effectively insulates the spring assembl and i'elt pad it from the metallic portion of the buck.

We have found it necessary to provide a further covering over the electrode 72, and for this Purpose a cloth 8i may be used, which may be cotton or other suitable material, following, the usual practice of covering the buck in a laundry ironing press. We have discovered, however, that for reasons to be later explained, certain advantageous results are obtained by providing a coveringv made of line continuous filaments of B'lasswoven into a cloth.

The electrode 12 is connected by the wire 40 to a stationary contact 82 (Figure 1) arranged to make connection with a contact 84 carried by the armature 63 of the relay 31 and connected direct- W to the point III in the control grid circuit. When the rela 31 is deenergized, the circuit to the electrode I2 is broken by the contacts 82 and 83, but when the relay is energized these contacts are made and the electrode I2 is connected to the control grid circuit.

In the first form of the invention illustrated in Figures 1 and 2, the ironing head I! of thepress Since the head is electrically connected to the frame 7 of the press. by means 'of its metal mountings, it follows that said frame may be connected by wire 84 to the wire H which is in turn connected to the cathode 4.0 of the tube 38.

When the relay 3'! is energized, therefore, electrically connecting the head 5 to'the electrode 12 has exactly the same effect as depressing the buttons 61 and 8B. The control grid 4! of the tube is kept positive, thus maintaining an anode current through the relay 3'' and holding the relay 3! energized, which in turn keeps the solenoid Ill energized and holds the press closed under the motive force of the pistonand cylinder means 20,

The action of the moisture in the work piece It between the electrode 12 and the metallic head I does not make a perfect electrical connection between said two electrodes. However, the resistances 54, and 56 are so chosen that the resistance between electrode 12 and head 8 caused by the moist material it and the steam evolved therefrom is low enough to alter the grid potential 40, 4| suillciently to cause the 'tube I8 to pass current and operate therelay 31.

The tube 38 is a gas-filled tube as previously stated, and has certain distinguishing characteristics known in the art. When such a tube'is used in the circuit herein described, the current passed by it to operate the relay 3'! will vary discontinuously from zero to maximum when the potential of control grid 4i is made more positive and from maximum to zero when the grid potential is varied in the opposite direction. This will prevent the relay 3! from chattering due to the slow change in resistance between the electrode 12 andhead i as the moisture is driven from the work piece it, and will always produce a positive action of this relay.

The foregoing action is made more positive because the combination of resistance 58 and condenser l1 acts to produce a D. C. bias on the grid 4| which also changes as the resistance between the electrodes changes and in the same direction. This will have the effect of producing a greater Tube 88--No..884 Thyratron Anode voltage-125 volts Grid voltage-85 volts Resistance 54-15900 ohms Resistance 55-25900 ohms Resistance 55-500,!)00 ohms Condenser II-.0i microfarad Coil 803500 ohms resistance Condenser 42-.5 microfarad In the above form of the invention, therefore, th operation may be as follows: The operator makes a lay of a damp garment It on the buck 3 and then depresses the two buttons 61 and 88. This sends the potential of the control grid 4| to wards that of the cathode 40 and the relay 31 operates, thus closing the contacts 64 and 65 and energizing the solenoid 30 to operate the valve 21 and close the press. The operator then holds the buttons 61 and II depressed for a short period of time until enough moisture is driven into the buck to penetrate the covering M, at which time the resistance between the electrode 12 and the head I will drop sumciently to cause the relay to lock closed through the contacts 82 and 83.

The operator can now remove her hands from the two-hand control buttons 81 and 88 and the press will stay closed, as long as sufllcient moisture remains between the head I and the electrode 11. However, this moisture is being continuously driven out as steam, and eventually the heat of the head and buck will dry the work to such an extent that resistance between the head 8 and electrode 12 will increase enough to give the control grid 4| of the tube 38 a sumcient negative potential to break the anode current and deenergize the relay 31, thus breaking the circuit through the contacts 64 and 65 and deenergizing the solenoid 30, which then permits the counterbalancing spring 23 to open the press.

In the case of a laundry press, the moisture is driven from the work down into the buck which is made porous for that purpose. However, if the top covering of the buck is made of moisture absorbing material, such as cotton cloth, it will act, not only to slow up the process of driving the moisture out of the work, but

will also increase the time required to do thework, as the covering also has to be dried.

Thus, the glass cloth covering II of Figure 3 has several important advantages over coverings heretofore used. It is non-absorbent of moisture. although extremely porous, and so permits the moisture to be quickly driven through it. with the result that the work in the press can be dried quicker. It is also strong and unaffected by heat at temperatures as high as 900 F. and will not scorch or stain, so that its life is much longer than muslin cloth coverings heretofore used.

As the temperature of'an ironing press head'is usually in the neighborhood of 350 F., higher temperatures might be used with the glass cloth covering, resulting in faster operation of the press. also as glass is a good insulator of it will hold the heat and maintain a hotter surface than the usual muslin covering. e surface of the glass cloth, also, is smooth "am which wili impart a better finish to the and smooth surface will reduce the on the work with the buck, as the opermakes the lay and removes the work, so that "he required for this purpose will be deof its inability to absorb moisre cloth will have less tendency to be stiffened and hardened with starch than the usual type oi bucir cover.

.En addition to the above advantages, the glass n covering iii aids in the quick and accurate case of the moisture responsive circuit. As moisture is present in the interstices of th, the circuit through it may be coma but such moisture will dry out very rapidas it is only on the surface of the strands, so

the circuit may be made to accurately red instantly work is dry.

dryness the finished work may be con as desired, by adjusting the variable re- .nce which in turn will control the variap tential of the control grid of the or changes in the moisture cone worn.

The (mailing; controlling circuit of Figures I and 2 as it takes a short interval of time for enough moisture to be driven into the buck to maize the necessary connection between the head 5 and electrode 'li. so that the moisture responsive circuit can taire over the control of the press, we

may prefer to provide an additional holding circult which will keep the press closing and hold it closed between the time that the closing buttons are released and the time that the moisture responsive circuit takes over the conrol. This will permit the operator to release the buttons whenever the head of the presshas moved a predetermined distance in the closing direction, this distance preferably being such that the head has closed sufliciently so that the operator cannot catch her hands between the head and buck.

To the above end, a; switch 85 may be operatively associated with the arm 8 of the press, so as to close when the head has almost reached its final closed position and then open when the head is completely closed. Such a switch may comprise a fixed contact 88 and a movable contact 87, mounted on a spring arm I! provided with a cam surface 88 arranged to contact a roller 90 which is mounted on the lower end of the arm 6. The cam surface 89 is so shaped that the roller 90 will engage the right-hand end of the cam surface, as shown in Figure 2, when the head is almost closed and will ride up over the cam surface, leaving the left end thereof when the head is completely closed, as indicated in dotted lines in Figure 1. The contacts 06 and 81 are therefore separated when the head I is open and also when completely closed or stalled against the buck 4. This switch 85 is closed only for a short period during the head travel, starting at a point when the head is close to the buck, and opening before full compression of, the buck padding has occurred.

The contact 86 may be connected to the wire 84 which leads to the cathode 40 of the tube 38, and the contact 81 may be connected by means of a wire 9! to the wire 80 which leads to the control grid circuit of the tube fill. The switch 85, therefore, acts exactly the same as the two switches 61 and B5, and as the head 5 and electrode 12, to change the potential of the control grid H of the tube 88 and thus operate the relay 311 When the head 5 approaches the bucls 3, therefore, contacts 86 and 8! close and take over the control of the press, so that thecperator can remove her hands from the buttons El and 88 as soon as the press is closed or almost closed. By the time the head ii begins to compress the worl: on the buck, there is then enough steam evolved to permit the moisture responsive circuit to take over the control of the press, so that when the contacts 86 and 81 separate again at the end of the closing movement, the press will be maintained closed by the action of the moisture responsive circuit.

As soon as the work has dried sufficiently to relay will open, and thus when the switch 85 is closed again on the return trip of the head 5, no effect will be produced on the circuit.

A normally closed releasing switch 92 may be provided in the circuit of the wire for releasing the press at any time, regardless of whether or not the work is dry, so that in case the operator desires to open the press to improve the lay of the work on the buck before the work is dry, she can do so by depressing the switch button 92. This breaks the locking circuit for the relay 81 and releases the relay, regardless of whether the switch or the electrode 12 is controlling the press.

The indicating means In some instance we may desire to provide an indicating means to visually show when the work is dry in the press. and to this end we may provide a contact 93 which may be insulatedly mounted on the armature 81 of the relay l1 and may be adapted to engage a fixed contact 94 when the relay 31 is deenergized. An electric light 95 may be connected by means of a wire 96 to the fixed contact 84, and the other terminal of the light may be connected by means of a wire 91 to the power supply wire 45. The contact 93 may be connected by means of a wire 98 to the other power supply wire 48. When the contacts 83 and N are separated owing to the relay 31 being held energized by moisture in the work, the electric light 95 will not be lit, but it will light as soon as the work has dried sufficiently to release the relay and thus indicate when the work is dry.

In some instances we may omit the automatic controlling feature of the press entirely, and use only the indicating device to visually notify the operator when the work is dry.

The electrodes of Fiflures 5 and 6 While we may prefer to use the electrode 12 as shown in Figures 1 to 4 inclusive, it may be desirable to provide both electrodes in the buck. To do this the arrangement of Figure 5 may be used in which a plurality of conducting strips 80, shown in this instance as wires, may be arranged longitudinally of the buck and may be connected together at one end by a. wire "0. A similar arrangement of conducting strips or wires HH may be spaced between the wires II in parallel relation thereto, and may be connected together at the other end of the buck and to the wire I02. The electrode wires 99 and MI may be applied to the cloth covering 11 in the same manner as the strips 18, and I9 of Figure 4 are applied, but they may also be woven into, the cloth or securedin any other desirable manner. The wires I and I02 may then take the place of the wires 80 and 84 of Figure 1, the remaining part of the circuit being exactly the same. 1

Under certain conditions we may desire to place the electrodes in the head of the press, in which case they may be arranged in accordance with the showing oi Figure '6. Here a head I03 is shown having inset insulating members I04 which may extend longitudinally of the head from end to end thereof, so that they may be engaged by any article which may be placed in the press,

and these insulating members may carry electrodes I04, the'whoie under-surface of the insulating insets and electrodes being flush with the under-surface oi the head.

In the case oi a laundry press the work usually has insulation characteristic when dry and hence the electrodes may actually contact with the work, as in the arrangement oi Figure 6, and the current between the electrodes may actually pass through the work. In other types of machines where the article being operated on has conductive characteristics, the electrode arrangements shown in Figures 1 to 5 inclusive should be used. In the embodiment shown in Figure 1 to 4, an insulating layer II is provided between the electrodes, and it is the moisture in this layer which causes'the humidity responsive circuit to take over the control of the pressand the disappearance of this moisture which then causes the press to open. In the arrangement of Figure 5 the moisture both in outerlayer 8| and inner layer 'l'l acts to produce a varying resistance between the electrodes, and the current does not pass through the work. Whether or not the article has electrical conductivity is immaterial in these particular cases.

It should be noted in the case of a laundry press that the moisture is driven into the layers 8i and 11 by the simultaneous actionoi heat and pressure. 'Either one, however, may be used alone, ii desired, or any other method of driving the moisture out of the work may be used, depending on the particular treatment of the article by the machine.

General discussion of invention the operator initially closes the press and the moisture responsive circuit takes over the control.

While the application of the invention to laundry presses makes use of the reduction of moisture in the article, or, in other words, the drying and pressure-ironing of the article, to release the press, it.will be noted that the operating relay oi the moisture responsive circuit operates in one way when suillcient moisture is present between the electrode i2 and head 5 of the press to reduce the resistance of the path between these two elements, and in another way when the resistance of this path is increased. In other words, it responds to both wetness and dryness. Therefore the invention is equally adaptable to use on machines in which moisture is added to an article, th article being first dry, and the operation of the machine controlled when sumcient moisture has been added to operate the control relay.

It will be seen that the invention is particularly advantageous in connection with laundry ironing presses as the press may be made to open automatically whenever the work is dry, thus avoiding the danger oi over-ironing and thus spoiling the finish of the work or the, scorching thereof, or or releasing the press before the work is completely dry or under-ironed so that it will have to be pressed over again.

' The moisture responsive control device may he trol for a machine which acts when the moisture A content of an article being operated on by the machine varies through a predetermined amount. The invention has been shown as an automatic timer applied to a laundry ironing press for opening same th moment the laundry work is pressure-ironed. However, it will be understood that this timer may be applied to any type of machine 'where'it is desired to control the machine in some manner by variation 0(. moisture in the article passing through the machine.

This humidity control apparatus has been shown in combination with an electrically-operated two-hand controlled press (Figures 1 and 2). In some instances, this humidity control may be arranged so that the operator may hold the press closed until the moisture responsive circuit takes over the control, whereas in other instances, the switch ll of Figures 1 and 2 may be added to take over the control or the press between the time that invention.

incorporated in the press when the press is manufactured, or it may be manui'acturedand sold as .a, unit which may be easily applied to existing presses to produce the highly desirable eii'ect or automatically opening the press at the moment when the work is ironed.

This invention is presented to fill a need for a new, faster, and more emcient pressing machine,

particularly for laundry and garment pressing which will produce a more uniform run of finished work. It is understood that various modifications in the structure. as well as changes in mode of operation, assembly, and manner of use, may and often do occur to those skilled in the art, especially after benefiting from the teachings of an Hence it will be understood that this disclosure is illustrative of preferred means oi embodying the invention in useful form by explaining the construction, operation and advantages thereon What is claimed is:

l. A machine for pressing and drying moist articles comprising a pair of cooperating pressing members, at least one of said members being heated, and at least one having an operating movement relative to the other, actuating mechanism for operating the movable member into pressing coaction with the other member including a motor, a control element for controlling the energization of the motor, operator controlled means for eflecting the operation of the control element to energize the motor including a balanced electric circuit having two conditions oi balance,- means operating to hold the control element operated a predetermined time after being'initiaily operated while the press is closing, and means connected with said circuit and responsive to variations in electrical resistance effected by the drying out or the moisture from the article being pressed to cause the circuit to change from one condition of balance to the other and operate the control element to de-energize the motor.

2. A press for pressing and drying moist, ar-

ticles comprising a pair of cooperating pressing end at least one being operable toward and from the other into and out of pressing coaction with the other, actuating mechanism for operating the a current to pass between the same through the moisture released from the article, the electrodes being connected with said circuit, means con nected with the circuit responsive to the variations in resistance between the electrodes effected by the drying out of the moisture from the article being pressed to cause said circuit to change from one condition of balance to the other to opercw the control element to de-energize the motor, and means connected with said balanced circuit to hold the control element energized a predetermined time otter the press closes a predetermined distance.

3. A press for pressing and drying moist articles comprising a pair of cooperating pressing members having an opening and closing movement,

at least one oi said members being movable toward and irom the other into and out of pressing coection with the other, and at least one of the members being heated, a porous covering on one of said members, the other of said members being electrically conductive, actuating mechanism for operating the movable member to close the press including a motor, a control element 101" controlling the energization of the motor, operator controlled. means for efiectlng the operation of the control element to energize the motor including r, balanced electric circuit having two conditions of balance, an electrode connected with said circuit and lnsulatingly mounted within the porous covering, means to cause the control element to remain operated a predetermined time when the press is closed a predetermined distance, the conductive member being connected with said balanced circuit, and means responsive to the variations in resistance between the electrode and said conductive member efiected by the drying out 0! the moisture from the article being pressed to cause said circuit to change from one condition of balance to the other and operate the control element to tie-energize the motor.

4. A press ior pressing and drying moist articles comprising a. pair of cooperating pressing members having an opening and closing movement, at least one of said members being movable toward and from the other into and out of pressing coaction with the other, actuating means for operating the movable member including a motor, a. control element for controlling the energization of the motor, operator controlled means for effecting the operation of the control element to energize the motor including a balanced electric circuit having two conditions of balance, an electrode connected in said circuit insulatingly mounted on one of said members, the other 0! said members being electrically conductive, means controlled by the closing movement of the press to hold the control element operated for a predetermined period during the closing movement of the press, and means responsive to variations in resistance between the electrode and the conductive member efiected by the drying out of the moisture from the article being pressed to cause said circuit to change from one condition of balance to the other and operate the control element to de-energlze the motor.

JAMES C. LEDBE'I'I'ER. EDWARD M. PRITCHARD. ELBERT W. SHERMAN. 

